The present invention relates generally to software tools for parametric studies with respect to missiles. More specifically, the present invention relates to a software tool which performs parametric studies using Euler and boundary layer solvers and which generates input data for conventional software analysis tools. Corresponding software and a storage medium for storing same are also disclosed.
During the past decade, significant advances have been made in the field of computational fluid dynamics (CFD). These include improvements in computational speed, numerical algorithm efficiency, and modeling (turbulence and combustion). Because of this progress, it is now commonplace to see accurate CFD solutions to very complex, large scale, three-dimensional flowfields. It should be noted, however, that a number of limitations remain. First, existing CFD solvers are quite complex and, thus, extensive training is required on the user's part prior to generating a solution. More specifically, the user must be trained not only in basic aerodynamics, but also in computational domain development and numerical methods. Second, the computational costs are still extensive. Complex problems or cases can still take days, weeks, or even months, of expensive workstation or supercomputer time to solve. Because of these limitations, parametric type design studies are often infeasible and, therefore, the use of CFD as an engineering design/development tool has been limited.
One software tool which has been adapted for use in problems amenable to CFD is the “ZEUS” flowfield solver, i.e., ZEUS code, which is a supersonic space marching Euler solver capable of computing both internal and external flowfields. The ZEUS algorithm was originally developed and described by Wardlaw et al. in documents such as:                (1) Wardlaw, A. B.; Davis, S. F.; and Priolo, F. J., A Second Order Gudonuv's Method for Supersonic Tactical Missile Computations (NSWC TR 86-506, December 1998);        (2) Hsieh, T. and Priolo, F. J., Generation of the Starting Plane Flowfield for Supersonic Flow Over a Spherically Capped Body (NSWC TR 84-484, May 1985);        (3) Wardlaw, A. B. and Priolo, F. J., Applying the Zeus Code (NSWC TR-86-508, December 1986);        (4) Wardlaw, A. B. and Baltakis, F. P., “An Integral Boundary Layer Procedure for Tactical Missiles,” (AIAA 92-1026, Aerospace Design Conference, Irvine, Calif., February 1992); and        (5) Wardlaw, A. B.; Priolo, F. J.; and Solomon, J. M., A Multiple Zone Method For Supersonic Tactical Missiles(NSWC TR 85-484, June 1986).It should be mentioned that all of the above-identified documents are incorporated herein by reference for all purposes.        
While Zeus Code is applicable to a wide variety of problems, e.g., supersonic flight conditions, there are a number of limitations in the original code which make it difficult to implement on a routine basis, e.g., early in the design phase of a missile. The following difficulties are frequently encountered in the exemplary process of optimizing the design of a missile:                (1) For each geometry under consideration, the user must develop a Fortran source code that provides a geometric description of the missile surface. In addition, code that specifies the control surfaces and switching logic for the boundary conditions must be generated.        (2) The user must be familiar with a number of separate codes in order to implement a ZEUS run. These include a separate code for each of the following tasks:                    (a) Cone/Blunt—Generate an initial profile by running one of the two codes;            (b) Convert—Convert the initial profile to a form readable by ZEUS;            (c) ZEUS—Solves the Euler form of the equations of motion; and            (d) BL—Performs a boundary layer analysis of the inviscid flowfield.            It will be appreciated that since the user must understand all of the inputs/outputs from each of the above codes, this significantly increases the amount of training required.                        (3) The setup time required before executing the code can be significant (typically on the order of hours/days). In addition, if parametric studies are desired, a separate set of input files must be generated for each case under consideration. This is both a time consuming and error prone process when a large number of cases are desired.        (4) Inherent limitations (space marching) in the ZEUS code prevent the solution of any flowfield with subsonic regions.        
What is needed is a software tool that could significantly reduce both the costs and turnaround time associated with CFD solutions of missile type geometries with arbitrary control surfaces. More specifically, what is need is a software tool which would minimize the required training, reduce the setup/execution time, minimize the costs associated with obtaining computational fluid dynamic solutions, and extend the range of applications for the Zeus code.